Many critical electrically-powered systems include one or more battery backup units that provide backup power to the system in the event of a loss of utility power. Battery backup units, however, can degrade over time to a point of not being capable of providing adequate backup power to the system in the event of loss of utility power.
Some batteries, which may be referred to as smart batteries, may include a built-in battery management unit (BMU) which is configured to deduce the state of the cells of the battery based on internally measured voltage and current. In some cases, a smart battery may be configured to indicate when it can no longer meet certain performance criteria. For example, as a battery ages, the full-charge capacity (i.e., the total Amp-hours available at a specified discharge current) for that battery declines over use. When the BMU detects that the full-charge capacity for a battery has fallen below some predetermined threshold, the BMU may indicate that the battery is no longer good. However, this predetermined threshold, as well as other performance criteria, is set by a manufacturer of the smart battery and is not appropriate for all load types. In some cases, a load on a particular battery may require a greater or lesser full-charge capacity. In these cases, the smart battery may report that it is no longer good well after a replacement is actually needed (risking failure of critical systems) or before replacement is actually needed (resulting in inefficient replacement of battery resources).
At least some embodiments of the invention address these and other problems, individually and collectively.